In order to compare the different adaptive ability of rubber seedlings to irradiance change among six varieties (‘GT1’,‘RRIM600’,‘PR107’,‘Yunyan 77-4’,‘Yunyan 77-2’ and ‘Reyan 523’),we grew the seedlings of each variety in four irradiance levels (100%,50%,25%,5%) for one year,then we compared some biochemical parameters of seedling leaves at dry and rainy season.The results indicated:(1)For each variety,there were significant differences for SOD,SS,Suc,Chl,Chl a/b,SP and RMP among four irradiances,and the varieties also have significant effect on these parameters.(2)For each variety,in dry season,SS and Chl decreased and SOD,SP,Suc,Chl a/b,Pro and MDA increased significantly when compared with rainy season.(3)For all six varieties,SP,SS,Suc,SOD and MDA decreased with the decreasing irradiance.(4)Seven parameters (SP,SS,Suc,SOD,Pro,Chla/b and MDA) were found that are strongly correlated with physiological adaptation to irradiance.(5) Comprehensive evaluation with subordinate function method,we found ‘RRIM600’,‘Yunyan 77-4’ and ‘Yunyan 77-2’ have stronger,while ‘Reyan 523’ has weaker adaptive ability to irradiance change,and ‘GT1’ and ‘PR107’ are intermediate.